I think we should change the way we discuss generations in gaming.
Generation 1 is 2D, stationary controller gaming (Atari 2600, Sega Genesis, PS2, etc). Generation 2 is 2D gaming with motion controls (Kinect, Wii). Generation 3 is VR/AR/3D. So, Switch is generation 1 and 2. I can't wait to see what we get in gen 4.
But, if we stick with same, boring generation classification system, I'd put Switch in gen 8. In much the same way that an older brother and younger sister are part of the same generation, so are Wii U and Switch.